Packing ring



Mar. 27, 1923. 1,449,615.

IIIIIIIIIII G.

Patented Mar. 27, 1923.

UNITED STATES .PATENT OFFICE.-

NELSO1\T W. MCLEOD, OF S'1. LOUIS, MSSOURI, ASSIG-NOR, BY MESNEASSIGNMENTS, T0

WALTER -A. ZELN ICKER,

OF ST. LOUIS, 1VHSSOURI.

PACKING RING.

Oontinuation of application Serial No. 477,036, filed June 13, 1921.This application flled February 14,

. 1922. Serial No. 536,48}.

To all whom t may concern:

Be it known that I, NELSON V. MCLEOD,

a citizen of the United States,.0f America,

Rings, of which the following is a full, clear,

and exact description, reference being had to the accompanying drawings,forming a part of this specification.

This invention relates to' improvements in packing rings and moreparticularly for packing rings adapted for use in engine pistons. Priorto this invention, engines have been provided with expariding pistonrings which do not properly engage the cylinder until their peripheralfaces are worn away by frictional engagement with the cylinder. \Vhen anordinary piston ring is applied to an engine, it is necessary to operatethe engine for several hours before the periphery of the ring willapproximately fit the cylinder. This is, of course, undesirable and itis especially expensive in the manufacture of engines. For example, inthe manufacture of internal combustion engines, it is customary to runeach engine for several hours. The object of this preliminary run is tomake the peripheral face of the ring conform approximately to thecylinder walls. For these reasons, automobile manufacturers prefer touse piston rings made of strong, heavyresilient material adapted to veryfirmly engage the cylinder walls and thereby wear away the contactingfaces of the rings and cylinder walls without unnecessary loss of time.However, actual experience has shown that it is necessary to operate anengine about five hours to obtain the desired contact between thecylinder walls and the Ordinary heavy expansible single rings.

An object of the present invention is to produce a packing ring whichwill very readily conform to and closely fit the friction surface towhich it is applied. More specifically stated, an object is to produce aresilient piston ring having a friction face portions of which willquickly wear away soas to conform the face to the cylinder wall in abrief period of time, thereby eliminating the expense of a longcontinued preliminary operation of the engine. The body of the ring maybe made of any suitable material, such as resilient cast-iron which hasbeen found to be most desirable for piston rings, and the friction facemay be made of relatively soft material. make the thickness of thecoating of soft metal such that even if completely worn off, the gap atthe open ends of the ring will never exceed the limit of practicalutility.

As an illustration of a simple form ofthe invention I have shown acast-iron rin member having a coating of relatively so metal cohering toits peripheral face. The soft coating is a thinuniform film of metalpreferably formed by electro-plaoing the cast-iron.

Figure 1 is an enlarged elevation of the piston ring embodying thefeatures of this invention.

Figure 2 is an enlarged transverse section showing a portion of thepiston in which the ring is mounted and a portion of the cylinderengaged by the ring.

1 designates a resilient ring member preferably made of cast-ironandprovided with a thin, uniform coating of relatively soft metal 2 on itsperipher al face. The.soft

metal 2 may be any one of a number of.

Preferably I- metals, such as copper or zinc, .or alloys that willsuggest themselves to the" person skilled in the art. I prefer copper orzinc. 3 designates a portion of a'piston having a groove in which thering is m0unted, an'd 4 designates a portion of a cylinder engaged bythe soft metal coating on the periphery of the ring.

Vhen a new ring is applied to a cylinder, it will not conform preciselyto the circular inner face of the cylinder. Under ordinary conditions, aring of this kind will initially contact'with the cylinder at a fewseparated points, and to obtain the desired close contact around theperipheryof the ring, it is necessary to operate the engine until theperiphery of the ring is worn to approximately the shape of thecylinder.

The friction-responsive element 2 is a thin film of soft metal coheringto the periphery of the resilient metal body of the plated on theresilient cast-iron will give satisfactory results. It is not necessaryto electro-plate all of the faces of the ring men1bcr. for only theperiphery of the packing ring engages the cylinder, and undue wear onthe side faces of the ring is undesirable.

Thethickness of 2/ 1000 of an inch recited in the preceding paragraphconstitutes only one embodiment of my invention. I do not wish to belimited to any specific dimension. In all cases, however, the thicknessof the coating or layer of soft metal should be such that it willreadily wear off at the points of intimate contact between the ring andthe cylinder or at the points of maximum wall pressure. This will bringabout the result that at the end of the preliminary run the ringpresents a bearing surface which is composed partly of the hard metaland partly of the soft metal.

The thin, uniform film of soft metal 2 is firmly united with theresilient body portion of the ring, so the friction at the element 2will not cause it to pee] from the resilient metal to which it isintegrally connected.

The packing ring has the usual separated ends adapted to lap each otherwhen the ring is contracted and forced into an engine cylinder. When anew ring is placed in service, some portions of the film of soft metalwill be rapidly worn away to make the ring approximately conform to thecylinder, and the friction will then be substantially uniform throughoutthe periphery of the ring. As the soft metal gradually wears from thering, it is forced into the pores and minute depressions in the enginecylinder, thereby imparting a smooth glaze to the cylinder wall, andthis tends to reduce the friction between the ring and thetcylinder.

The very gradual wearing away of the pcriphery of the ring results in aslight expansion of the ring and a slight widening of the gap at thelapped ends of the ring. However, there is only a very slight increasein the width of the gap, for the thickness of the film of soft metal issuch that the soft metal can be worn away without materially changingthe width of the gap at the lappcd ends of the ring.

While in the figures of the, drawings l have shown the film of softmetal in exaggerated thickness, this has been done for illustrativepurposes only.

The advantages result-ing, from the structure disolosed are obvious. Aquick seatng of the ring and a reduction of the duration of thepreliminary run is one of them. With this advantage is coupled the-factthat the wearing resistance of the ring in actual operation is greaterthan the rings hitherto used.

I claim 1. A piston packing ring comprising a resilient ring member, anda cylinder engaging wearing element consisting of a film of relatively'soft metal uniformly coated on the periphery of said resilient ringmember.

2. .A piston packing ring coniprising a resilient ring member, and acylinder engaging wearing element consisting of a film of relativelysoft metal electro-plated on the periphery of said resilieht rmgmember.

3. A piston packing ring comprising a resilient ring member providedwith a thin coating of soft metal on its outer fate, said coating beingof such dimensions that will permit it to be worn off in spots duringthe preliminary run on the engine.

4. A piston packing ring compris'ing a resilient ring member of hardmetalprovidcd with a thin coating of soft metal on its bearing face,said coating being of such dimensions that after a preliminary run thebearing surface is partly of hard metal and partly of soft metal.

5. A piston ring comprising a split ring formed of cast iron, and acoating of relatively soft quick wearing material located on its wearingface. y

6. A metallic piston ring having a surface layer of a metal differentfrom that of the body of the ring and electroplated on the latter.

In testimony that I claim the foregoing I hereunto aflix my signature.

NELSON W. MCLEOD.

